The complex design of integrated circuits today contribute to the increased circuit density of the chips utilized. However, as the chip density increases, the thermal properties of the circuit package becomes an important concern. The ability to remove heat generated from the high-powered and highly dense integrated circuits in a semi-conductor packaging becomes vital to the function and performance of the electronics. The initial approach taken to cooling electrical devices through the use of air convection has been replaced by water cooling methods. As the density and integration level of these circuits increases, the amount of heat dissipated by the system can no longer be adequately removed through the use of conventional air convection techniques. Furthermore, the physical size of an effective air convection heat sink is prohibitive, a main concern when using compact devices such as lap-top computers.
Indirect water cooling approach using cold plates quickly has become a selected approach to eliminate the large amount of heat generated by the high power semiconductor modules on large size PC boards or cards. Nonetheless, indirect water cooling approach has not eliminated all heat removal concerns, particularly when a direct or immersion cooling approach is used.
The geometry of the circuit board and its modules have contributed to new concerns, compounding the heat removal problems. Often an array of electronic modules are mounted on a flat printed circuit board. The modules may be of different shapes and geometry and therefore, the height of a particular module can be much higher or lower than that of its neighbors. Due to a large variance of card flatness and module heights, a misalignment of module top surfaces can lead to a complicated set of problems affecting module powers, uneven thermal resistance and even solder failures caused by mechanical stress applied to the joints.